Rechargeable battery for hand-guided electromechanical tools

ABSTRACT

A rechargeable battery ( 1 ) for hand-guided electromechanical tools, having a plurality of rechargeable battery cells ( 10 ) which are electrically connected to one another by means of electrical cell connectors ( 110 ), wherein the electrical cell connectors ( 110 ) are fixed to a cell connection frame ( 120 ), which is provided on one pole side ( 19 ) of the rechargeable battery cells ( 10 ), for the purpose of simplified mounting of the electrical cell connectors ( 110 ) on the rechargeable battery cells ( 10 ). Furthermore, an electromechanical tool, in particular a cordless screwdriver, a drill, a circular saw, a jigsaw, a sander, a garden appliance, having a rechargeable battery ( 1 ) according to the invention.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a 35 USC 371 application of PCT/EP2008/056043 filedon May 16, 2008.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a rechargeable battery for hand-guidedelectromechanical tools, in which the rechargeable battery has manyrechargeable battery cells electrically connected to one another. Theinvention also pertains to an electromechanical tool having arechargeable battery according to the invention.

2. Description of the Prior Art

All hand-guided, portable, electrically operated hand tools in which amotor is a usually inseparable component of the tool are calledelectromechanical tools. Examples are power drills, rechargeable batterycells, circular and saber saws, right-angle sanders, and other powersanders, as well as various garden tools, depending on the design, suchas electric hedge shears. Rechargeable batteries or nonrechargeablebatteries for such tools should have the highest possible capacity, anda sturdy construction that resists even relatively strong impacts, andshould be capable of being produced both simply and furthermoreeconomically.

Electrical connections of rechargeable battery cells or battery packcells inside a rechargeable battery are embodied in the prior art by wayof separate cell connections. As a result, particularly withrechargeable batteries that have many rechargeable battery cells, theeffort of assembly is high and there are problems in positioning thecell connections. If the electric cell connections are not prefixed bymeans of a separate device frame or held on the rechargeable batterycells by means of clamping or retaining elements before welding to thepoles of the rechargeable battery cells is done, then geometricimprecisions can result in positioning the cell connections. This leadsto quality problems with the rechargeable batteries, and in later use,the likelihood of failure of the rechargeable battery can be increased.

German Patent DE 100 03 740 C1 discloses a battery with a heatdissipator, and a plurality of battery cells are interconnected with oneanother in the battery. These battery cells are connected in parallel,and each three battery cells are connected electrically by means of acell connector and form a battery cell packet. The batter cell packetsof the battery are electrically connected by means of current bridgesand connected in series. The electrical cell connection and currentbridges are each provided separately inside the battery. For dissipationof heat generated in the battery, a flat cooling plate is provided on atleast one face end of the battery and is at least indirectly in thermalcontact with the cell connections and the current bridges.

OBJECT AND SUMMARY OF THE INVENTION

It is one object of the invention to disclose an improved rechargeablebattery. In particular, it is an object of the invention on the one handto dispense with pre-fixation of the separate electrical cellconnections on the rechargeable battery cells, without having to acceptsacrifices in quality in the production of the rechargeable battery. Itis furthermore an object of the invention to disclose a robust,economical rechargeable battery that furthermore should be capable ofbeing produced quickly. It is moreover an object of the invention torealize an electromechanical tool having a rechargeable battery of theinvention.

According to the invention, for simplified, faster and more-economicalassembly of the rechargeable battery, an electrical cell connector forrechargeable battery cells of the rechargeable battery is affixed to acell connection frame, which is preferably of plastic and which can beprovided on one pole side of the rechargeable battery. The electricalcell connector and the cell connection frame form the cell connectionaccording to the invention by means of which the rechargeable batterycells can be connected electrically. Preferably, the cell connectionframe is spray-coated or coated from behind on the cell connection orcell connections. According to the invention, the separate cellconnections that are usual in the prior art are preferably connected toone another by a plastic spray-coating in the form of a frame, thuscreating an integrated component comprising a plurality of cellconnections and the cell connection frame.

As a result, the effort and expense in rechargeable battery assembly inparticular is reduced, and constant quality of the welded connections ofthe individual rechargeable battery cells to the electrical cellconnectors is guaranteed, since the cell connection frame can bepositioned exactly on a cell cluster of the rechargeable battery.Because of the ease of assembly of the cell connection according to theinvention, secure electrical cell connectors are obtained with littlefluctuation in quality. As a result, the rechargeable battery and thecell connection is inexpensive, economical, and reliable. The cellconnection of the invention is well designed with regard to temperatureperformance and electrical insulation performance. The cell connectionis furthermore safe and reliable because of influence on the geometry ofits cell connection frame, since this frame can be adapted torequirements inside the rechargeable battery.

The cell connection according to the invention preferably hasrectangular or circular through recesses, on or in which contactportions of the electrical cell connectors are disposed. These throughrecesses, in an assembled cell connection, are disposed on or above thepoles of the rechargeable battery cells of the rechargeable battery. Theapplicable contact portion for a welding tool, in particular a weldingelectrode, is accessible through the respective through recess, and as aresult, a pole of a rechargeable battery cell can be welded to theapplicable contact portion.

In preferred embodiments of the invention, the electrical cellconnectors has a curved transitional portion, and the contact portionsof the cell connection can be seated resiliently on the poles of therechargeable battery cell. This simplifies welding of the contactportions to the applicable poles. In the case of flat cell connectors,it is naturally possible for the contact portions also to be embodied asspring contacts.

By means of protrusions and/or recesses, for instance, on the side ofthe cell connection frame that faces toward the poles of therechargeable battery cells, the cell connection of the invention can bepositioned on the rechargeable battery cells. In other words, by meansof a fastening portion formed integrally onto or into the cellconnection frame, it is possible to position the cell connection framequickly and simply on the rechargeable battery cells. Next, the contactportions of the electrical cell connectors are welded to the poles ofthe rechargeable battery cells. In embodiments of the invention, thecell connection can be locked, clipped or glued to one or a plurality ofrechargeable battery cells and/or to a housing of the rechargeablebattery.

In the cell connection of the invention, the cell connections canfurthermore be secured or provided intermittently inside the cellconnection frame, and/or the cell connections can intermittently beflush with an outside of the cell connection. In the latter embodiment,space is usually saved compared with the first one mentioned. The plainportions of the cell connections can be electrically insulated from ahousing of the rechargeable battery or separately.

Further preferred embodiments of the invention will become apparent fromthe other dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in further detail below in terms ofexemplary embodiments, in conjunction with the accompanying drawings. Inthe drawings:

FIG. 1 shows a first embodiment of a cell connection according to theinvention in a top view;

FIG. 2 shows the cell connection of FIG. 1 in an assembled state on aplurality of rechargeable battery cells, in a partly sectional sideview;

FIG. 3 shows a second embodiment of the cell connection of the inventionin an assembled state on a plurality of rechargeable battery cells, in apartly sectional side view; and

FIG. 4 shows a third embodiment of the cell connection of the invention,in a top view.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention is described in further detail below in terms of arechargeable battery for hand-guided electromechanical tools. However,the invention not meant to be limited to such hand-guided tools butinstead pertains to rechargeable batteries in general. For instance, theinvention can be employed with rechargeable batteries for motor vehiclesthat have internal combustion engines or drive systems of electric motorvehicles. It is also possible for instance to use the invention forrechargeable batteries for portable electronic devices, drives, such asdrives for constructing models, and in cell phones, cameras, and thelike.

When the term “cell connector” is used hereinafter, it is meant toinclude the term cell terminal for one pole of the rechargeable battery;that is, the invention also pertains to that portion of a rechargeablebattery at which the cell connection, in the form of a rechargeablebattery pole, is visible on an outside of the rechargeable battery.Dashed lines in the drawings also designate edges that cannot be seen.Conversely, dot-dashed lines represent optional or additionalembodiments of the invention.

FIGS. 1 and 2 show a rechargeable battery 1 which can also be embodiedas a rechargeable battery train or rechargeable battery packet or anonrechargeable battery. A housing of the rechargeable battery 1 is notshown. The rechargeable battery 1 has four rechargeable battery cells10, and an electrical connection of two rechargeable battery cells 10 iseffected via an electrical cell connector 110. It is understood to bepossible to provide the rechargeable battery 1 with one more or fewerrechargeable battery cells 10, and to connect them electrically inseries or parallel as needed.

The electrical cell connectors 110, preferably embodied in flat andpreferably striplike form, are provided on one pole side 19 of therechargeable battery cells 10 of the rechargeable battery 1. Theelectrical cell connectors 110 are disposed in part on and/or inside acell connection frame 120. That is, the cell connection frame 120 andthe electrical cell connectors 110 are combined into one component. Thecell connection frame 120 here comprises an electrical insulatingmaterial and is preferably made from a plastic. In particular, the cellconnection frame 120 is integrally injected, or spray-coated, orspray-coated from behind, onto the individual electrical cell connectors110 by means of an injection molding process.

The electrical cell connectors 110 and the cell connection frame 120 ofthe invention together yield the cell connection 100 of the invention,which is seated on the pole side 19 of the rechargeable battery cells10. Contact portions 112 of the electrical cell connectors 110 eachcontact the rechargeable battery cells 10 at a respective electricalpole 12. Preferably, the contact portions 112 are welded to therespective pole 12, preferably spot-welded. However, it is also possibleto make an electrical contact of a contact portion 112 with theapplicable pole 12 in some other way, which can even be done only viaspring forces, for instance. Weld spots 113 connecting the contactportions 112 to the, poles 12 can be seen in FIGS. 1 and 4.

Particularly if the contact portions 112 are to be welded to the poles12, the cell connection frame 120 has through recesses 122, so that awelding tool (welding horn, electrode, sonotrode) can reach the vicinityof a contact portion 112 that is to be welded to the applicable pole 12.For that purpose, the through recesses 122 are provided on or in aregion of the cell connection frame 120 on or in which the contactportions 112 of the electrical cell connectors 110 are provided. Thethrough recesses 122 are circular, elliptical or rectangular, forinstance, but arbitrary shapes of the through recesses 122 can of coursebe used as well. If welding of the contact portions 112 to the poles 12is dispensed with, then the through recesses 122 can be left out, andthe cell connection 100 can form part of the housing of the rechargeablebattery 1.

In the exemplary embodiment shown in FIG. 2, the electrical cellconnectors 110 are secured by one portion inside the cell connectionframe 120. The region of the electrical cell connector 110 located inthe vicinity of the through recess 122 is preferably guided in a regionof the through recess 122 via a curved transitional portion 111. In thisrespect it is preferable for curved transitional portion 111 to guidethe contact portion 112 of the electrical cell connector 110 in a regionbelow an underside 129 of the cell connection frame 120. In other words,the free contact portions 112 of the applicable cell connectors 110protrude from the underside 129 or outside of the cell connection frame120. The contact portions 112 are located parallel to the underside 129and preferably also parallel to a top side 128 of the cell connectionframe 120.

To compensate for a difference in height among the rechargeable batterycells 10, the various contact portions 112 are disposed in two planesparallel to one another. However, in other embodiments of the invention,it is possible for all the contact portions 112 of the electrical cellconnectors 110 to be disposed in one plane, in which case the applicablepoles 12 of the rechargeable battery cells 10 are then also disposed inone plane.

In FIG. 1, it can be seen that the cell connection 100 or the cellconnection frame 120 is aligned with both its long sides with therechargeable battery cells 10, and as can also be seen in FIG. 2, withits two transverse sides it extends beyond the respective lateralrechargeable battery cell 10. However, it is also possible to selectother configurations. For instance, it is possible for the transverseand long sides of the cell connection frame 120 to be aligned with therechargeable battery cells 10 or protrude into it or beyond it (in topview). It is also possible to dispose the cell connection frame 120asymmetrically or partly symmetrically with respect to the rechargeablebattery cells 10. This is indicated in part by the embodiments shown indashed lines in FIG. 1. FIG. 1 also shows a rechargeable battery cell 10that is enlarged compared with the rechargeable battery cells 10 shownin FIG. 2.

To simplify “centering” or preassembly of the cell connection 100 on therechargeable battery cells 10, the cell connection 100 can have assemblyprotrusions 124 on its underside 129 facing toward the rechargeablebattery cells 10. These protrusions are shown in dot-dashed lines inFIG. 2. A plurality of assembly protrusions 124 (see also FIG. 4) may beprovided. It is moreover possible to provide only one assemblyprotrusion 124, which in the assembled state extends all the way aroundor only partway around the rechargeable battery cells 10 of therechargeable battery 1.

Another possibility of providing the cell connection 100 according tothe invention on the rechargeable battery cells 10 is shown in FIG. 3.Here the contact portions 112 of the electrical cell connectors 110protrude into the corresponding through recesses 122 of the cellconnection frame 120. In other words, the electrical cell connectors 110are disposed entirely inside an outer boundary of the cell connectionframe 120. Correct seating of the cell connection 100 on therechargeable battery cells 10 is effected by means of recesses 126,which are provided in the cell connection frame 120. The recesses 126trace the applicable portions of the rechargeable battery pack cells 10,so that protrusions formed by the recesses 126 come to rest in freespaces between two or four rechargeable battery cells 10. As shown inFIG. 3, the cell connection 100 according to the invention may beembodied as overall shorter than the rechargeable battery cells 10disposed side by side. FIG. 3 furthermore shows an embodiment of theinvention with an assembly protrusion 124 which is provided on one longend of the cell connection frame 120 and which in the assembled stateconforms to one or a plurality of rechargeable battery cells 10.

FIG. 3 furthermore shows an embodiment in which a top side 128 (indot-dashed lines) of the cell connection frame 120 is aligned with atleast one electrical cell connector 110 (FIG. 3, top center). Naturally,it is also possible for a plurality of electrical cell connectors 110,or all of them, to be aligned by at least one portion with the top side128 of the cell connection frame 120 (this is not shown in the drawing).In such embodiments of the invention, it is preferable that theelectrical cell connectors 110, in those portions on which they havematerial contact with the cell connection frame 120, have correspondingrecesses, preferably through recesses, into which the fluid plastic canflow in the spray-coating process, so as to affix the electrical cellconnectors 110 to the cell connection frame 120. Naturally, it is alsopossible for this to be done only later upon assembly of the electricalcell connectors 110 on an already-completed cell connection frame 120.

FIG. 4 shows an embodiment of the cell connection 100 according to theinvention in which two rows each of four rechargeable battery cells 10are connected electrically in series to one another. This can be seenfrom the arrangement of the poles 12 of the rechargeable battery cells10. A cell connection 100 according to the invention located oppositethat face end then connects the rechargeable battery cells 10 not shownin FIG. 4 accordingly. That side then also has the poles 12 of therechargeable battery 1. In all the embodiments of the invention, it ispossible for this side of the rechargeable battery 1 to be electricallyinterconnected with conventional cell connections.

FIG. 4 furthermore shows an alternative preferred electrical contactportion 112 (FIG. 4, bottom center), which has two tongues, and eachtongue is connected electrically to the pole 12 of the rechargeablebattery cell 10 by means of a weld spot 113; the two tongues areseparated from one another via a gap. FIG. 4 furthermore shows analternative rechargeable battery cell 10 in its cross section, which isconstructed as approximately square or nearly rectangular. As a result,the space inside the rechargeable battery 1 can be utilized moreeffectively.

FIG. 4 furthermore shows alternative assembly protrusions 124. On theone hand, one such assembly protrusion 124 is provided in all fourcorner regions of the cell connection frame 120. Alternatively or inaddition, it is possible to provide the assembly protrusions 124 in amiddle region of the cell connection frame 120. This is shown as anexample by means of two peglike assembly protrusions 124.

The invention is of course also usable with only a single electricalcell connector 110 that connects two rechargeable battery cells 10 toone another. In that case, the cell connection frame 120 is preferablyembodied as a land between the two contact portions 112 of theelectrical cell connector 110.

The foregoing relates to the preferred exemplary embodiments of theinvention, it being understood that other variants and embodimentsthereof are possible within the spirit and scope of the invention, thelatter being defined by the appended claims.

The invention claimed is:
 1. A rechargeable battery for hand-guidedelectromechanical tools, having a plurality of rechargeable batterycells which are connected to one another by means of electrical cellconnectors, wherein, for mounting of the electrical cell connectors onthe plurality of rechargeable battery cells, the electrical cellconnectors are affixed to a cell connection frame which is provided onone pole side of the plurality of rechargeable battery cells, whereinelectrical contact portions of the electrical cell connectors areprovided on or in through recesses of the cell connection frame orprotrude at least partway into them, and a through recess is disposedon/above one pole of a rechargeable battery cell, wherein the electricalcell connectors have curved transitional portions, by means of which aseat of a contact portion, adjoining the transitional portions, of theelectrical cell connector on a pole of at least one of the plurality ofrechargeable battery cells is assured.
 2. The rechargeable battery asdefined by claim 1, wherein one side, which is oriented toward theplurality of rechargeable battery cells, of the cell connection framehas protrusions and/or recesses, by means of which the cell connectionframe is positioned on the plurality of rechargeable battery cells. 3.The rechargeable battery as defined by claim 1, wherein the cellconnection frame is locked to at least one rechargeable battery celland/or a housing of the rechargeable battery.
 4. The rechargeablebattery as defined by claim 2, wherein the cell connection frame islocked to at least one rechargeable battery cell and/or a housing of therechargeable battery.
 5. The rechargeable battery as defined by claim 1,wherein the electrical cell connector is provided with one portioninside the cell connection frame.
 6. The rechargeable battery as definedby claim 4, wherein the electrical cell connector is provided with oneportion inside the cell connection frame.
 7. The rechargeable battery asdefined by claim 1, wherein one portion of at least one of theelectrical cell connectors is flush with a surface of the cellconnection frame which is situated away from the plurality ofrechargeable battery cells.
 8. The rechargeable battery as defined byclaim 6, wherein one portion of at least one of the electrical cellconnectors is flush with a surface of the cell connection frame which issituated away from the plurality of rechargeable battery cells.
 9. Therechargeable battery as defined by claim 1, wherein the cell connectionframe comprises a plastic and is integrally injection-molded onto theelectrical cell connectors by means of an injection-molding process. 10.The rechargeable battery as defined by claim 1, wherein the cellconnection frame is embodied in one piece.
 11. The rechargeable batteryas defined by claim 1, wherein all of the electrical cell connectors aremounted to the cell connection frame at the same time.
 12. Therechargeable battery as defined by claim 1, wherein the cell connectionframe has an underside and a contact portion of the electrical cellconnectors lies below the underside so that the contact portion of theelectrical cell connectors protrude from the underside of the cellconnection frame.
 13. The rechargeable battery as defined by claim 1,wherein a point at which the electrical cell connectors are affixed tothe cell connection frame and the electrical cell connectors lie indifferent planes.
 14. The rechargeable battery as defined by claim 1,wherein the contact portions of the electrical cell connectors areseated resiliently on the poles of the battery cells.
 15. Therechargeable battery as defined by claim 1, wherein the cell connectionframe comprises a fastening portion configured to fasten the cellconnection frame to the battery cells.
 16. The rechargeable battery asdefined by claim 1, wherein the electrical cell connectors are affixedto the cell connection frame to form one component.